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- Author or Editor: H. Kimura x
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Abstract
There are two types of lakes in the vicinity of the nuclear fuel cycle facilities in Rokkasho-mura. One is a brackish lake, Obuchinuma Lake, and the other is a freshwater lake, Takahokonuma Lake. Tritium concentrations in Obuchinuma Lake had a good negative correlation with salinity at any sampling point and period. We consider that the water of Obuchinuma Lake has been only slightly influenced by precipitation depending on the ratio of seawater and river water of the Futamata River. Tritium concentrations in Takahokonuma Lake ranged from 0.6 to 1.5 Bq·1-1, and were higher than that in precipitation in Rokkasho-mura. Tritium concentration in rivers flowing into the lakes ranged from 0.7 to 2 Bq·l-1, and were higher than that in the precipitation. It is assumed that ground waters with higher levels of tritium inflow into the rivers.
Abstract
Isothermal titration microcalorimetry has been applied to investigate the compatibility testing of risperidone oral solution with soft-drinks and the interaction with tea tannin such as (–)-epigallocatechin, (–)-epicatechin, theaflavin and their gallates. In aqueous solution, risperidone was exothermically bound to tea tannin with binding affinity (103–104 M–1), small enthalpy and entropy changes reflecting van der Waal’s interaction to form an insoluble complex at 1:1 molar ratio. The heat effect of risperidone titrated into soft-drinks containing tannin was exothermic and proportional to the quantity of the complex. While, no significant heat effect was found for risperidone titrated into a pet-bottled water and an infusion of parched barley without tea tannin. These results were agreed with stability testing of risperidone in some soft-drinks by HPLC method.
The glass transition temperature of a copolymer depends not only on chemical composition but also on its comonomer sequences. This experimental fact is explained by Barton's and Johnston's equations. Their equations, though complicated, become simple, if a suitable parameter is used to describe the comonomer sequences. It is shown that with these new expressions, their equations can be used to understand glass transition temperatures of two additional types of copolymers, compatible multiblock copolymers and homopolymers with various tacticities treated as steric copolymers.
Abstract
To reveal the denaturation mechanism of lysozyme by dimethyl sulfoxide (DMSO), thermal stability of lysozyme and its preferential solvation by DMSO in binary solutions of water and DMSO was studied by differential scanning calorimetry (DSC) and using densities of ternary solutions of water (1), DMSO (2) and lysozyme (3) at 298.15 K. A significant endothermic peak was observed in binary solutions of water and DMSO except for a solution with a mole fraction of DMSO (x 2) of 0.4. As x 2 was increased, the thermal denaturation temperature T m decreased, but significant increases in changes in enthalpy and heat capacity for denaturation, ΔH cal and ΔC p, were observed at low x 2 before decreasing. The obtained amount of preferential solvation of lysozyme by DMSO (∂g 2/∂g 3) was about 0.09 g g−1 at low x 2, indicating that DMSO molecules preferentially solvate lysozyme at low x 2. In solutions with high x 2, the amount of preferential solvation (∂g 2/∂g 3) decreased to negative values when lysozyme was denatured. These results indicated that DMSO molecules do not interact directly with lysozyme as denaturants such as guanidine hydrochloride and urea do. The DMSO molecules interact indirectly with lysozyme leading to denaturation, probably due to a strong interaction between water and DMSO molecules.
Abstract
A large reprocessing plant of spent nuclear fuel is now under construction in Rokkasho-village, Aomori Pref. Japan. We carried out the survey of tritium concentration in water vapor and precipitation on the top of Mt. Hakkoda, to grasp the behavior of tritium in the environment of Aomori Pref. The tritium concentration in water vapor and precipitation tended to increase from spring through summer. Deuterium concentration in water vapor is lower than precipitation and the effect of the isotope separation by evaporation was observed. The tritium concentration in water vapor, however, is a little bit higher than precipitation. The tritium concentration in water vapor showed the similar change on the top of Mt. Hakkoda and also the wide region covering Rokkasho-village from Aomori-City. Also, on the top of Mt. Hakkoda the correlation was observed between the tritium concentration in water vapor and ozone concentration.
Abstract
Three commercial nuclear fuel cycle facilities, a reprocessing plant, an uranium enrichment plant and a low level radioactive waste disposal center, have been constructed or are in partial operation at Rokkasho-mura in Aomori prefecture, about 700 km north of Tokyo. A monitoring program has been settled on the modulation between Japan Nuclear Fuel Ltd. (JNFL) and Aomori Prefectural Govemment. The basic goal of environmental monitoring is to make sure that the dose equivalent received by the public, living around the facilities, is much lower than the annual dose equivalent limit. The target is as follows: (1) to estimate the dose equivalent received by the public, (2) to understand the accumulation of radioactive materials in the environment and (3) to estimate the influence on the environment due to unexpected release from the nuclear facilities and to make judgement for the enforcement of routine monitoring or not. This paper describes the contents of the monitoring program such as the object of nuclides, measuring/sampling point, kinds of samples etc.
Abstract
Coordination states of Eu(III) in anion exchange resin (AG 1X8) systems with LiCl-H2O/alcohol mixed media were determined from the luminescence lifetimes and the emission spectra of Eu(III). The sorption equilibrium of Eu(III) was discussed on the basis of the correlation between the distribution coefficients and the coordination states in the solution and resin phases. The sorption of Eu(III) was mainly caused by the formation of an anionic Eu(III)-chloro complex in the resin phase, which was enhanced by the decrease of 'free' water activity due to the addition of alcohol. The effect of ethanol added was larger than that of methanol.
Abstract
A non-destructive method for determining the amount of actinoids has been developed. The method is based on thermal neutron coincidence counting and employs a selective detection of neutrons resulting from the spontaneous fission of actinoids. The detection system is described in detail and the measurement results of244Cm as an example are presented. The results show that the measured fission rate of244Cm is consistent with the fission rate calculated from ENDF/B-V data and that the amount of244Cm can be determined within about 5% accuracy even in the presence of a large amount of actinoids, for example, up to 2.6·106, 3.6·104, or 1.6·103 times in the mass ratio of239Pu,241Am, or240Pu to244Cm, respectively.
Abstract
The complex formation of LaCl3 with dipivaloylmethane (dpm) was investigated in a view of the applicability to a rapid chemistry. It was found that the complex formation of lanthanum chloride with dpm in a gas phase was recognized and a volatile LaCl2 (dpm) which was formed by substitution of a chloride atom in LaCl3 by dpm molecule was mainly produced. A temperature dependence of LaCl2 (dpm) formation was examined and the activation energy of the reaction was deduced.
Abstract
Aomori Prefectural Govemment and Japan Nuclear Fuel Limited started environmental radiation monitoring around Nuclear Fuel Cycle Facilities in April 1989. External radiation is measured by NaI(TI) scintillator and Themoluminescence dosimeter. The level of external radiation is relatively low in the winter due to snow. We have collected terrestrial samples of drinking water, soil, agricultural products and marine samples of seawater, sea sediment, seafood, etc. periodically. We have measured many radionuclides and fluoride in these samples. In soil sample,239+240Pu ratio to137Cs was almost constant at all sampling points. A correlation was observed between salinity and concentration of tritium, uranium and fluoride in lake water of Lake Obuchinuma. The correlation between137Cs and239+240Pu in lake sediment was observed in each lake.
